1. Field of the Invention
The present invention is directed particularly to apparatus for treating workpieces in a chamber under the action of a hot gas, and, more particularly, to a device including valve means for distributing the flow of the hot gases.
2. Description of Related Art
In devices of the type to which the present invention relates, charges or batches are processed in a chamber under the action of a hot gas which is supplied to the charge by a special inlet device. In such apparatus, a chamber is provided which may be subjected to overpressure or underpressure.
In the art to which the present invention relates, a charge or workpiece can be subjected to a heat treatment and/or a chemical treatment by exposing the charge or workpiece to the action of heated gases. On the one hand, this can be accomplished by placing the charge into a heat treatment furnace within which a static gas atmosphere is heated. Alternatively, the charge can be exposed to a constant hot gas flow produced within the chamber by means of suitable inlet and outlet apertures.
Installations of this type are known in which a heat treatment furnace is equipped with a system of gas inlet and gas outlet apertures. Initially, the gas is heated by a gas preheater and then introduced from one side and it is thus directed to the charge which is to be treated. The gas then exits again on the opposite side and so as to achieve a better distribution of gas flow, the gas inlet system may be located in the center of the furnace.
In that case, gas will flow from the center symmetrically toward both sides over the charge or batch being treated and will then be exhausted at the opposite side.
Such processes have the disadvantage that homogeneous distribution of gas cannot be satisfactorily accomplished. Apart from that, there results directed gas flows which give rise to an interference factor and, thus, are undesirable. In particular, in numerous chemical processes, a homogeneous circulation of the charge on all sides by the gas participating in the reaction is of considerable importance.